Inside a spare campaign office in Bucks County on a cloudyOctober day, the middle-aged Baltimore resident and a dozen or so others were preparing to go door to door in search of voters. Wallace, a Democrat trying to unseat Republican U.S. Rep. Brian Fitzpatrick, had a suggestion for winning over people in the suburban swing district.

"I always start by asking them what their big issue is," he said. "But then, the umbrella issue I find works best across the board, including among Republicans and independents, is corporate money in politics."

"One word you'll never hear cross his lips is Republican," Wallace said. "But every time Trump needs him, he's right there. So don't let people get away with thinking he's a moderate."

Kirschman is in the Philadelphia suburbs this weekend because she wants Democrats to take back the House — and the First District race is one of the most competitive congressional elections in the country. With Democrats now speculating control of the chamber could come down to a handful of contests, voters in Bucks County will likely have an outsize role in determining whether Republicans are expelled from power.

"We feel like we need to spread our wings and fly to the hot campaign," said Kirschman. "We've got to flip Congress."

Bucks County residents have a history of splitting their tickets: At various times, voters have supported Hillary Clinton, Republican U.S. Sen. Pat Toomey, Democratic Gov. Wolf, and former Republican Gov. Tom Corbett. Mostrecentpolls in the First District, which includes a portion of Montgomery County, have found Fitzpatrick ahead by a slim margin.

The race is of such national importance that journalists from France, Germany, and Japan have studied it. Indivisible Baltimore, Swing Left, and University of Pennsylvania students have flocked to the region to help Wallace.

Whether they're successful may depend on whether Bucks County voters, sometimes described as "parochial" by political analysts, see this year's election as a referendum on Trump — or their self-described "centrist" Republican incumbent.

An anti-Trump campaign in a swing district

Wallace, a 67-year-old multi-millionaire philanthropist, never ran for office until this year.

For the last 15 years, he ran a family foundation with his wife, which distributed grants to groups attempting to fight climate change, protect women's rights, and overhaul the criminal justice system, as well as liberal media organizations. David Hunter, an environmental law professor at American University, called the Global Wallace Fund "one of the more cutting-edge foundations on climate justice." (Hunter noted that he formerly received funding from the foundation, which also has supported groups on whose boards he sits.)

Earlier in his career, Wallace worked as a lawyer for a U.S. Senate committee and a director at the National Legal Aid and Defender Association.He said he decided to run because he was frustrated with Trump.

"Trump got elected and started betraying many of the promises that he made to work for working people," he said. "We were also losing something about who we are as a nation, something about our democratic values, our respect for the institutions of law and the press."

Much of Wallace's campaign has focused on tying his opponent to Trump and national Republicans. His TV ads have assailed Fitzpatrick for voting for Trump's tax cuts, which he said "exploded our debt by $2 trillion." He noted in a recent debate that Republican House Speaker Paul Ryan fund-raised for Fitzpatrick this month — a visit Fitzpatrick didn't publicize.

Wallace has also repeatedly highlighted that "84 percent" figure, from the data-journalism website FiveThirtyEight. Fitzpatrick counters that the number is based on a fraction of Congress' votes.

Wallace's strategy of nationalizing the election could succeed in a district where Trump is unpopular. Like many other well-educated suburbs in the U.S., the president's job approval rating is underwater in the First District, according to polling by the New York Times and Siena College.

Fitzpatrick has touted votes against repealing the Affordable Care Act, NRA-backed legislation requiring states to honor other states' concealed-carry gun permits, and a bill opposing a carbon tax. He also comes from a political family with a centrist identity, and has won the support of labor unions and gun-control groups.

Wallace, meanwhile, has unique weaknesses as a candidate: Though he was born in Bucks County, he lived in Washington and South Africa until recently. He also inherited his wealth and was born into a minor Democratic royal family — his grandfather was a vice president under Franklin D. Roosevelt — giving firepower to Republicans who brand him as out of touch.

But Wallace has the cash to fight back: He's spent more than $8 million of his own funds on the race, which is one of the most expensive in the nation. Outside groups have also poured money into the campaign, most of it against Wallace.

Wallace's campaign seems most centered on turning out Democrats. He has embraced the surge in liberal activism in the wake of Trump's election, campaigning alongside gun-control and environmental activists, as well as students. He's also raised the issue of climate change to a degree not often seen in this year's congressional races.

Still, in a place like Bucks County, he needs to win over some independents. Wallace tells voters that he was hired as a U.S. Senate attorney by Republicans. Like Fitzpatrick, he has described himself as independent. He has also declined to say whether he will vote for Nancy Pelosi for House speaker if Democrats win the majority.

Control of the U.S. House ‘could come down to this race’

A Democratic committee person told the Inquirer and Daily News that he's voting for Fitzpatrick. A registered independent said he's casting a ballot for Wallace. A lifelong Republican woman said she's likely voting a straight ticket this year — for Democrats.

Bucks County is home to many swing voters, which means that even though political observers say all politics is local here, the district also often moves with the nation. In 2006, Fitzpatrick's brother, former Rep. Mike Fitzpatrick, was ousted in a Democratic wave — and then swept back into the House amid the tea party revolt of 2010.

With days to go till Election Day, Wallace reflected on the national importance of his campaign.

"It could come down to this race," he said. "If we lose this race and we come down to 22 seats" — meaning the Democrats fail to take the majority by a single seat — "I'll feel pretty miserable and I'll blame myself."

But, he said, that "just increases your determination."

If Wallace is lucky, there are more voters in suburbs like Mark Popjoy than not.

After an October debate between Wallace and Fitzpatrick in Doylestown, Popjoy, an engineer from Montgomery Township, said he is voting for the Democrat.

He used to vote for Republicans. In many ways, he's exactly the kind of voter that Fitzpatrick should have a chance of winning over. But the GOP has "moved away" from him in recent years, Popjoy said.

Popjoy, in particular, said he thought Fitzpatrick's vote for tax cuts was financially irresponsible.

While he talked about the changing GOP, an aide for Fitzpatrick approached Popjoy and his wife, Ellie Reader. She asked if they wanted a copy of a Washington Post article, which found that Democrats had falsely claimed Fitzpatrick voted against safeguarding people with pre-existing conditions.